Wireless power transmission system, and method for controlling wireless power transmission and wireless power reception

ABSTRACT

A wireless power transmission system, and a method for controlling wireless power transmission and wireless power reception are provided. According to an aspect, a method for controlling a wireless power transmission may include: detecting a plurality of target devices used to wirelessly receive power; selecting a source resonating unit from among a plurality of source resonating units, based on the amount of power to be transmitted to one or more of the plurality of target devices, a coupling factor associated with one or more of the plurality of target devices, or both; and wirelessly transmitting power to a target device using the selected source resonating unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/646,728, filed Jul. 11, 2017, which is a continuation of U.S. patentapplication Ser. No. 14/597,503, filed Jan. 15, 2015, now U.S. Pat. No.9,729,013, which claims the benefit of U.S. patent application Ser. No.13/424,433, filed Mar. 20, 2012, now U.S. Pat. No. 8,946,940, whichclaims the benefit under 35 U.S.C. 119(a) of a Korean Patent ApplicationNo. 10-2011-0025739, filed on Mar. 23, 2011, in the Korean IntellectualProperty Office, the entire disclosures of which are incorporated hereinby reference for all purposes.

BACKGROUND 1. Field

The following disclosure relates to wireless power transmission andreception.

2. Description of Related Art

Wireless power refers to type of energy that is transferred from awireless power transmitter to a wireless power receiver. Accordingly, atypical wireless power transmission system includes a source device anda target device. The source device may wirelessly transmit power, andthe target device may wirelessly receive power. The source deviceincludes a source resonator, and the target device includes a targetresonator. A magnetic coupling or resonance coupling may be formedbetween the source resonator and the target resonator.

Due to characteristics of a wireless environment, that distance betweena source resonator and a target resonator may be highly likely to varyover time, and matching requirements to match the source resonator andthe target resonator may also change. Thus, the power transmissionefficiency may be reduced.

SUMMARY

According to one general aspect, a method for controlling a wirelesspower transmission may include: detecting a plurality of target devicesused to wirelessly receive power; selecting a source resonating unitfrom among a plurality of source resonating units, based on the amountof power to be transmitted to one or more of the plurality of targetdevices, a coupling factor associated with one or more of the pluralityof target devices, or both; and wirelessly transmitting power to atarget device using the selected source resonating unit.

The detecting may include: broadcasting a wake-up request signal; andreceiving one or more response signals in response to the wake-uprequest signal from one or more of the plurality of target devices,wherein one or more of the response signals comprises information on anidentifier (ID) of a corresponding target device, information on theamount of power to be used in the corresponding target device, or both.

The detecting may include: broadcasting wake-up request signals usingthe plurality of source resonating units; and receiving response signalsin response to the wake-up request signals from the plurality of targetdevices.

The selecting may include: selecting the source resonating unittransmitting the largest amount of power to one or more of the pluralityof target devices from among the plurality of source resonating units.

The selecting may include: verifying a first power amount of power to betransmitted to a first target device adjacent to a first sourceresonating unit, and a second power amount of power to be transmitted toa second target device adjacent to a second source resonating unit; andselecting the first source resonating unit when the first power amountis greater by a predetermined value than the second power amount, andselecting the second source resonating unit when the second power amountis greater by the predetermined value than the first power amount.

A first target resonator of the first target device may be different insize or in the number of turns of a coil from a second target resonatorof the second target device.

The selecting may include: selecting the source resonating unit havingthe highest coupling factor with respect to one or more of the pluralityof target devices from among the plurality of source resonating units.

The selecting may include: verifying a first power amount of power to betransmitted to a first target device adjacent to a first sourceresonating unit, and a second power amount of power to be transmitted toa second target device adjacent to a second source resonating unit;verifying a coupling factor with respect to one or more of the firsttarget device and the second target device, when a difference betweenthe first power amount and the second power amount is less than or equalto a predetermined value; and selecting the source resonating unithaving the higher coupling factor from among the first source resonatingunit and the second source resonating unit.

The selecting may include: verifying a first power amount of power to betransmitted to a first target device adjacent to a first sourceresonating unit, and a second power amount of power to be transmitted toa second target device adjacent to a second source resonating unit; andturning on or off the first source resonating unit and the second sourceresonating unit, when a difference between the first power amount andthe second power amount is less than or equal to a predetermined value.

The method may further include: turning off the selected sourceresonating unit when power reception of the target device adjacent tothe selected source resonating unit is terminated; and turning on asource resonating unit adjacent to a low power device used to wirelesslyreceive power from the target resonator among the plurality of sourceresonating units.

The amount of power transmitted wirelessly from the selected sourceresonating unit to the target device adjacent to the selected sourceresonating unit is determined based on the amount of power to be used inthe target device adjacent to the selected source resonating unit, theamount of power to be used in the low power device, or both.

The selecting may include: turning on the selected source resonatingunit; and turning off one or more source resonating units other than theselected source resonating unit. According to another general aspect, awireless power transmitter may include: a detector configured to detecta plurality of target devices used to wirelessly receive power; acontroller configured to select a source resonating unit from among aplurality of source resonating units, based on the amount of power to betransmitted to one or more of the plurality of target devices, acoupling factor associated with one or more of the plurality of targetdevices, or both; and a power transmitting unit configured to wirelesslytransmit power to a target device using the selected source resonatingunit.

The detector may include: a communication unit configured to broadcast awake-up request signal, and to receive response signals in response tothe wake-up request signal from one or more of the plurality of targetdevices, wherein one or more of the response signals comprisesinformation on an identifier (ID) of a corresponding target device,information on the amount of power to be used in the correspondingtarget device, or both.

The controller may select, from among the plurality of source resonatingunits, a source resonating unit transmitting the largest amount of powerto one or more of the plurality of target devices, or a sourceresonating unit having the highest coupling factor with respect to oneor more of the plurality of target devices.

The controller may include: a first processor configured to verify afirst power amount of power to be transmitted to a first target deviceadjacent to a first source resonating unit, and a second power amount ofpower to be transmitted to a second target device adjacent to a secondsource resonating unit; and a second processor configured to select thefirst source resonating unit when the first power amount is greater by apredetermined value than the second power amount, to select the secondsource resonating unit when the second power amount is greater by thepredetermined value than the first power amount, and to verify acoupling factor with respect to one or more of the first target deviceand the second target device and to select a source resonating unithaving a high coupling factor from among the first source resonatingunit and the second source resonating unit when the difference betweenthe first power amount and the second power amount is less than or equalto the predetermined value.

The second processor may turn on or off the first source resonating unitand the second source resonating unit, when the difference between thefirst power amount and the second power amount is less than or equal tothe predetermined value.

When power reception of the target device adjacent to the selectedsource resonating unit is terminated, the controller may turn off theselected source resonating unit, and turn on a source resonating unitadjacent to a low power device used to wirelessly receive power from thetarget resonator among the plurality of source resonating units.

The amount of power transmitted wirelessly from the selected sourceresonating unit to the target device adjacent to the selected sourceresonating unit may be determined based on the amount of power to beused in the target device adjacent to the selected source resonatingunit, on the amount of power to be used in the low power device, orboth.

When power reception of the low power device is terminated, thecontroller may control the amount of the power wirelessly transmittedfrom the selected source resonating unit to the target device, based onthe amount of the power to be used in the target device, the amount ofpower received to the target device, or both.

The power transmitting unit may include the plurality of sourceresonating units, wherein one or more of the plurality of sourceresonating units comprises a plurality of resonators arranged in anarray.

The plurality of source resonating units may be identified by IDs of theplurality of source resonating units, wherein the controller recognizeslocations of the plurality of target devices using the IDs.

According to yet another general aspect, a wireless power receiver mayinclude: a communication unit configured to transmit, to a wirelesspower transmitter, information on an identifier (ID) of the wirelesspower receiver, information on the amount of power to be used in thewireless power receiver, or both; a power receiving unit configured towirelessly receive power from a source resonating unit, to wirelesslyreceive power from a target resonator of another wireless powerreceiver, or both; and a controller configured to disconnect a load whenpower reception is terminated.

The power receiving unit wirelessly may receive the power from thesource resonating unit when the amount of the power to be used in thewireless power receiver is greater than the amount of power to be usedin the other wireless power receiver, wherein the power receiving unitwirelessly receives the power from the target resonator when the amountof the power to be used in the wireless power receiver is less than theamount of the power to be used in the other wireless power receiver.

The power receiving unit may include a target resonator, wherein thetarget resonator of the power receiving unit is different in size or inthe number of turns of a coil from the target resonator of the otherwireless power receiver.

Other features and aspects will be apparent from the following detaileddescription, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a wireless power transmission system.

FIG. 2 is a diagram illustrating computing a coupling factor in awireless power transmission system.

FIGS. 3 through 7 are diagrams illustrating charging multiple targets.

FIG. 8 is a diagram illustrating one configuration of a wireless powertransmitter.

FIG. 9 is a diagram illustrating one configuration of a powertransmitting unit of FIG. 8.

FIG. 10 is a diagram illustrating one configuration of the sourceresonating unit of FIG. 9.

FIG. 11 is a diagram illustrating one configuration of a wireless powerreceiver.

FIG. 12 is a diagram illustrating a method for controlling wirelesspower transmission.

FIGS. 13 through 19B are diagrams illustrating various resonatorstructures.

FIG. 20 is a diagram illustrating one equivalent circuit of a resonatorof FIG. 13.

Throughout the drawings and the detailed description, unless otherwisedescribed, the same drawing reference numerals will be understood torefer to the same elements, features, and structures. The relative sizeand depiction of these elements may be exaggerated for clarity,illustration, and convenience.

DETAILED DESCRIPTION

The following detailed description is provided to assist the reader ingaining a comprehensive understanding of the methods, apparatuses,and/or systems described herein. Accordingly, various changes,modifications, and equivalents of the methods, apparatuses, and/orsystems described herein will be suggested to those of ordinary skill inthe art. The progression of processing steps and/or operations describedis an example; however, the sequence of and/or operations is not limitedto that set forth herein and may be changed as is known in the art, withthe exception of steps and/or operations necessarily occurring in acertain order. Also, description of well-known functions andconstructions may be omitted for increased clarity and conciseness.

FIG. 1 illustrates a wireless power transmission system. As shown, asource device 110 may include a source unit 111 and a source resonator115. The source unit 111 may receive energy from an external voltagesupply to generate power. The source device 110 may further include amatching control 113 to perform resonance frequency matching and/orimpedance matching.

For example, the source unit 111 may include an alternating current(AC)-to-AC (AC/AC) converter, an AC-to-direct current (DC) (AC/DC)converter, and a DC-to-AC (DC/AC) inverter. The AC/AC converter mayadjust, to a desired level, the signal level of an AC signal input froman external device. The AC/DC converter may output DC voltage at apredetermined level by rectifying an AC signal output from the AC/ACconverter. The DC/AC inverter may generate an AC signal (e.g., in a bandof a few megahertz (MHz) to tens of MHz) by quickly switching the DCvoltage output from the AC/DC converter.

The matching control 113 may be configured to set at least one or bothof a resonance bandwidth of the source resonator 115 and an impedancematching frequency of the source resonator 115. In some embodiments, thematching control 113 may include at least one of a source resonancebandwidth setting unit and a source matching frequency setting unit. Thesource resonance bandwidth setting unit may set the resonance bandwidthof the source resonator 115. The source matching frequency setting unitmay be configured to set the impedance matching frequency of the sourceresonator 115. For example, a Q-factor of the source resonator 115 maybe determined based on a setting of the resonance bandwidth of thesource resonator 115 or a setting of the impedance matching frequency ofthe source resonator 115.

The source resonator 115 may transfer electromagnetic energy to a targetresonator 121. For example, the source resonator 115 may transfer powerto the target device 120 through magnetic coupling 101 with the targetresonator 121. The source resonator 115 may resonate within the setresonance bandwidth.

The target device 120 includes the target resonator 121, a matchingcontrol 123 to perform resonance frequency matching or impedancematching, and a target unit 125 to transfer the received resonance powerto a device or load.

The target resonator 121 may receive the electromagnetic energy from thesource resonator 115. The target resonator 121 may resonate within theset resonance bandwidth.

For example, the matching control 123 may set at least one of aresonance bandwidth of the target resonator 121 and an impedancematching frequency of the target resonator 121. In some instances, thematching control 123 may include at least one of a target resonancebandwidth setting unit and a target matching frequency setting unit. Thetarget resonance bandwidth setting unit may set the resonance bandwidthof the target resonator 121. The target matching frequency setting unitmay set the impedance matching frequency of the target resonator 121.For example, a Q-factor of the target resonator 121 may be determinedbased on a setting of the resonance bandwidth of the target resonator121 and/or a setting of the impedance matching frequency of the targetresonator 121.

The target unit 125 may transfer the received power to the load. Forexample, the target unit 125 may include an AC/DC converter and aDC-to-DC (DC/DC) converter. The AC/DC converter may generate a DC signalby rectifying an AC signal transmitted from the source resonator 115 tothe target resonator 121. The DC/DC converter may supply a predeterminedor rated voltage to a device or the load by adjusting a signal level ofthe DC signal.

For example, the source resonator 115 and the target resonator 121 maybe configured in a helix coil structured resonator, a spiral coilstructured resonator, a meta-structured resonator, and the like.

Due to external effects, such as, for example, a change in a distancebetween the source resonator 115 and the target resonator 121, a changein a location of at least one of the source resonator 115 and the targetresonator 121, and the like, an impedance mismatching between the sourceresonator 115 and the target resonator 121 may occur. The impedancemismatching may be a cause in decreasing an efficiency of powertransfer. Thus, when a reflected wave corresponding to a transmissionsignal that is partially reflected by a target and returned is detected,the matching control 113 may determine the impedance mismatching hasoccurred, and may perform impedance matching. The matching control 113may change a resonance frequency by detecting a resonance point throughwaveform analysis of the reflected wave. For example, the matchingcontrol 113 may determine a frequency that generates the minimumamplitude in the waveform of the reflected wave, as the resonancefrequency.

FIG. 2 illustrates computing a coupling factor in a wireless powertransmission system having a source resonator 210 and a target resonator220 spaced apart by a distance d. The source resonator 210 may have alength d1, and the target resonator 220 may have a length d2 and rotatedby an angle α measured clockwise from normal/vertical. A coupling factor“K” between the source resonator 210 and the target resonator 220 may becalculated using Equation 1, as follows.

$\begin{matrix}{K = \frac{W_{1}^{2} \times W_{2}^{2} \times {\cos(\alpha)}}{\sqrt{W_{1} \times W_{2}} \times \left( {W_{1}^{2} + d^{2}} \right)^{\frac{3}{2}}}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

In Equation 1, W₁ denotes the resonance frequency of the sourceresonator 210, W₂ denotes the resonance frequency of the targetresonator 220. When W₁ is equal to W₂ in Equation 1, the coupling factor“K” may be maximized. Additionally, when has a value close to “0,” thecoupling factor “K” may have a high value.

In one or more embodiments, the length d1 of the source resonator 210may be set to “2×W₁,” and the length d2 of the target resonator 220 maybe set to “2×W₂.”

FIGS. 3 through 7 illustrate charging multiple targets according tovarious charging scenarios.

In FIG. 3, power may be simultaneously transmitted to different kinds ofloads. A target device 310 may be located adjacent to a sourceresonating unit 330, and a target device 320 may be located adjacent toa source resonating unit 340. If the source resonating units 330 and 340are in the form of pads, the target devices 310 and 320 may be placed onthe source resonating units 330 and 340, respectively.

In FIG. 3, the target device 310 may require power of 5 Watt (W), andthe target device 320 may require power of 10 W. Thus, a wireless powertransmitter may transmit the power of 5 W to the target device 310, andmay transmit the power of 10 W to the target device 320. In someinstances, the target device 310 may be a low power device or a lowpower load. “Low power” as used herein may refer to a power requirementless than 10 W. On the other hand, the target device 320 may be a highpower device or a high power load for instance. “High power” as usedherein may refer to a power requirement greater than or equal to 10 W.Accordingly, loads or target devices may be classified based on theamount of power required by one or more of the target devices.

In FIG. 3, the source resonating unit 330 and the source resonating unit340 may be included in the wireless power transmitter. FIG. 8 shows oneconfiguration of the wireless power transmitter which will be furtherdescribed below. According to one or more embodiments, when power issimultaneously transmitted to the low power device and the high powerdevice, the wireless power transmitter may turn ON the source resonatingunit 340 adjacent to the high power device, and may turn OFF the sourceresonating unit 330 adjacent to the low power device. In FIG. 3, thetarget device 320 may wirelessly receive power from the sourceresonating unit 340, and the target device 310 may receive the powerfrom the target device 320. Accordingly, the target device 310 mayreceive the power from the target device 320 via magnetic coupling 1.Additionally, the target device 310 may receive power from the sourceresonating unit 340 via magnetic coupling 2.

A first target resonator of the target device 310 may be different insize or in the number of turns of a coil from a second target resonatorof the target device 320. For example, the first target resonator of thetarget device 310 may have a size larger than 1.1 to 2 times the size ofthe second target resonator of the target device 320.

FIG. 4 illustrates when power reception of a high power device isterminated.

Referring to FIG. 4, a target device 410 may be located adjacent to asource resonating unit 430, and a target device 420 may be locatedadjacent to a source resonating unit 440. When the source resonatingunits 430 and 440 are in the form of pads, the target devices 410 and420 may be placed on the source resonating units 430 and 440,respectively. Although it should be appreciated that the target devicescould be placed next to (or in the general vicinity of) the sourceresonating units, in some instances.

As shown in FIG. 4, when power reception of the target device 420 (e.g.,a high power device) is terminated, the source resonating unit 440 maybe turned OFF, and the source resonating unit 430 may be turned ON.Accordingly, the target device 410 may receive power from the sourceresonating unit 430. The terminating of the power reception of thetarget device 420 may indicate, for example, that the target device 420has completely received 10 W of power from the source resonating unit440. A wireless power transmitter may detect a reflected wave, and/orreceive a message from the target device 420 in order to determine thatthe power reception of the target device 420 has been terminated.

FIG. 5 illustrates when power reception of a low power device isterminated.

Referring to FIG. 5, a target device 510 may be located adjacent to asource resonating unit 530, and a target device 520 may be locatedadjacent to a source resonating unit 540. When the source resonatingunits 530 and 540 are in the form of pads, the target devices 510 and520 may be placed on the source resonating units 530 and 540,respectively. Although it should be appreciated that the target devicescould be placed next to (or in the general vicinity of) the sourceresonating units, in some instances.

In FIG. 5, when power reception of the target device 510 (e.g., a lowpower device) is terminated, the target device 510 may disconnect aload. And when the load is disconnected, a magnetic field between thetarget device 510 and the target device 520 may not be formed.

FIG. 6 illustrates simultaneously transmitting power to the same kind ofload.

Referring to FIG. 6, a target device 610 may be located adjacent to asource resonating unit 630, and a target device 620 may be locatedadjacent to a source resonating unit 640. When the source resonatingunits 630 and 640 are in the form of pads, the target devices 610 and620 may be placed on the source resonating units 630 and 640,respectively. Although it should be appreciated that the target devicescould be placed next to (or in the general vicinity of) the sourceresonating units, in some instances.

In FIG. 6, both the target device 610 and the target device 620 arereferred to as low power devices. However, in other instances, both thetarget device 610 and the target device 620 may be high power devices.In an embodiment, when a difference between a power amount P1 of powerto be transmitted to the target device 610 and a power amount P2 ofpower to be transmitted to the target device 620 is within apredetermined range, the target devices 610 and 620 may be classified asthe same kind of load. For example, when the difference between thepower amounts P1 and P2 is less than or equal to 2 W, the target devices610 and 620 may be classified as the same kind of load.

When loads are of the same kind, the coupling factor, or the powertransmission efficiency may be considered. A wireless power transmittermay be configured to verify a coupling factor with respect to each ofthe target devices 610 and 620, and may select a source resonating unithaving the higher coupling factor from among the source resonating units610 and 620. Accordingly, the selected source resonating unit having thehigher coupling factor may be turned ON, and the other source resonatingunit having the lower coupling factor may be turned OFF.

In FIG. 6, the coupling factor between the target device 620 and thesource resonating unit 640 may be greater than the coupling factorbetween the target device 610 and the source resonating unit 630.Accordingly, the source resonating unit 640 may be turned ON, and thesource resonating unit 630 may be turned OFF. As illustrated in FIG. 6,the target device 610 may receive power from the target device 620 viamagnetic coupling 1. Additionally, the target device 610 may alsoreceive power from the source resonating unit 640 via magnetic coupling2. The wireless power transmitter may determine the power transmissionefficiency of one or more of the target devices 610 and 620, bymeasuring a reflected power, or by receiving information on the powertransmission efficiency from each of the target devices 610 and 620.Additionally, the wireless power transmitter may select a sourceresonating unit having higher power transmission efficiency from amongthe source resonating units 630 and 640.

FIG. 7 illustrates transmitting power to the same kind of load insequence.

Referring to FIG. 7, a target device 710 may be located adjacent to asource resonating unit 730, and a target device 720 may be locatedadjacent to a source resonating unit 740. The source resonating units730 and 740 are in the form of pads, the target devices 710 and 720 maybe placed on the source resonating units 730 and 740, respectively.Although it should be appreciated that the target devices could beplaced next to (or in the general vicinity of) the source resonatingunits, in some instances. The source resonating units 730 and 740 may bealternately turned ON or OFF, to transmit the same amount of power tothe target devices 710 and 720.

FIG. 8 illustrates one configuration of a wireless power transmitter.

As shown, a wireless power transmitter 800 may include a detector 810, acontroller 820, and a power transmitting unit 830. Additionally, thewireless power transmitter 800 may further include a power generator840, a matching controller 850, a rectification unit 860, and a constantvoltage controller 870.

The detector 810 may be configured to detect a plurality of targetdevices that wirelessly receive power. The detector 810 may include acommunication unit to broadcast a wake-up request signal, and to receiveresponse signals in response to the wake-up request signal from each ofthe plurality of target devices. Additionally, the detector 810 mayfurther include a reflected power detector to detect reflected power.One or more of the response signals may include information on anidentifier (ID) of a corresponding target device, and information on theamount of power to be used in the corresponding target device.

The detector 810 may also receive location information of each of theplurality of target devices from the plurality of target devices. Thelocation information may be ID information of each of a plurality ofsource resonating units 831, 833, 835, and 837. For example, a firsttarget device adjacent to the source resonating unit 831 may receive anID Si of the source resonating unit 831 from the source resonating unit831, and may transmit, to the detector 810, a response signal includingthe received ID Si in response to the wake-up request signal. If thesource resonating unit 831 is in the form of a pad, the first targetdevice may be placed on the source resonating unit 831. For example,when two target devices are placed on the source resonating unit 831,the amount of power to be used in a corresponding target device may beobtained by adding amounts of powers to be used in the two targetdevices.

The power transmitting unit 830 may include the plurality of sourceresonating units 831, 833, 835, and 837. One or more of the plurality ofsource resonating units 831, 833, 835, and 837 may include a pluralityof resonators arranged in an array. Here, a target device adjacent tothe source resonating unit 831 will be referred to as a first targetdevice, and a target device adjacent to the source resonating unit 833will be referred to as a second target device.

The controller 820 may select a source resonating unit from among theplurality of source resonating units 831, 833, 835, and 837, based onthe amount of power to be transmitted to each of the plurality of targetdevices, or based on a coupling factor associated with each of theplurality of target devices. One or more of the plurality of sourceresonating units 831, 833, 835, and 837 may be positioned adjacent tothe plurality of target devices. Additionally, under the control of thecontroller 820, the power transmitting unit 830 may wirelessly transmitpower to a target device adjacent to the selected source resonatingunit, for instance, through a magnetic coupling between the selectedsource resonating unit and a target resonator of the target deviceadjacent to the selected source resonating unit.

The controller 820 may be configured to select, from among the pluralityof source resonating units 831, 833, 835, and 837, a source resonatingunit that transmits a large amount of power to one or more of theplurality of target devices, or a source resonating unit having a highcoupling factor with respect to each of the plurality of target devices.The controller 820 may turn ON the selected source resonating unit, andmay turn OFF source resonating units other than the selected sourceresonating unit.

In some instances, the controller 820 may include a first processor anda second processor. The first processor may be configured to verify apower amount P1 of power to be transmitted to the first target device,and a power amount P2 of power to be transmitted to the second targetdevice. When the power amount P1 is greater by a predetermined valuethan the power amount P2, the second processor may select the sourceresonating unit 831. The predetermined value may be set to variousvalues, for example, values in a range of 1 to 200 W. Additionally, whenthe power amount P2 is greater by the predetermined value than the poweramount P1, the second processor may select the source resonating unit833. In FIGS. 3 through 5, the predetermined value may be set to 4 W,and a difference between the power amounts P1 and P2 may be greater than4 W. Additionally, when the difference between the power amounts P1 andP2 is less than or equal to the predetermined value, the secondprocessor may verify a coupling factor with respect to each of the firsttarget device and the second target device, and may select a sourceresonating unit having a high coupling factor from both the sourceresonating units 831 and 833. In FIGS. 6 and 7, the predetermined valuemay be set to 1 W, and the difference between the power amounts P1 andP2 may be less than 1 W. Accordingly, when the difference between thepower amounts P1 and P2 is less than or equal to the predeterminedvalue, the second processor may alternately turn ON or OFF the sourceresonating units 831 and 833, as illustrated in FIG. 7.

When power reception of the first target device is terminated, thecontroller 820 may turn OFF the selected source resonating unit 831, andmay turn ON the source resonating unit 833 among the source resonatingunits 833, 835, and 837. The source resonating unit 833 may be locatedadjacent to a low power device that wirelessly receives power from thetarget resonator through magnetic coupling. For example, as illustratedin FIG. 4, the controller 820 may turn OFF the selected sourceresonating unit 440, and may turn ON the source resonating unit 430adjacent to the target device 410, for instance, the low power device.The source resonating units 440 and 430 of FIG. 4 may be the sourceresonating units 831 and 833 of FIG. 8, respectively, in someembodiments.

The controller 820 may control the power generator 840, and may controlthe amount of power transmitted through each of the source resonatingunits 831, 833, 835, and 837. Accordingly, the controller 820 maydetermine the amount of power that is wirelessly transmitted from theselected source resonating unit 831 to the first target device, based onan amount “PHIGH” of power to be used in the first target device, andbased on an amount “PLOW” of power to be used in the low power device.The first target device and the second target device may be a high powerdevice and a low power device, respectively, in some embodiments.

As illustrated in FIG. 3, under the control of the controller 820, thepower generator 840 may generate power, based on the amount of powertransmitted through magnetic coupling from the target device 320 to thetarget device 310. As the difference between the amounts “PHIGH” and“PLOW” increases, the magnetic coupling between the first target deviceand the second target device may be better formed. Accordingly, in asituation when there is an extremely large difference between theamounts “PHIGH” and “PLOW,” for example, when the difference is greaterthan or equal to than 10 W, the power transmission efficiency may behigher than when there is a small difference between the amounts “PHIGH”and “PLOW,” for example, the difference being less than or equal to than5 W.

When power reception of the low power device is terminated, thecontroller 820 may control the amount of power that is wirelesslytransmitted to the second target device, based on the amount of thepower to be used in the first target device, the amount of powerreceived to the first target device, or both.

The power generator 840 may generate power to be transmitted to awireless power receiver. The power generator 840 may generate powerunder the control of the controller 820. And the power generator 840 mayconvert a DC current of a predetermined level to an AC current by aswitching pulse signal (e.g., in a band of a few MHz to tens of MHz),and may generate power. Accordingly, the power generator 840 may includean AC/DC inverter. The DC current may be provided from the constantvoltage controller 870. The AC/DC inverter may include a switchingdevice for high-speed switching. When the switching pulse signal is“high” (i.e., at or near its maximum), the switching device may bepowered ON. When the switching pulse signal is “low” (i.e., at or nearits minimum), the switching device may be powered OFF. The matchingcontroller 850 may perform impedance matching between the powertransmitting unit 830 and the power generator 840. For example, thematching controller 850 may adjust impedances of one or more of theplurality of source resonating units 831, 833, 835, and 837 under thecontrol of the controller 820.

The rectification unit 860 may generate a DC voltage by rectifying an ACvoltage, for example, in a band of tens of Hz.

The constant voltage controller 870 may receive the DC voltage from therectification unit 860, and may output a DC voltage at a predeterminedlevel under the control of the controller 820. The constant voltagecontroller 870 may include a stabilization circuit configured to outputthe DC voltage at the predetermined level.

FIG. 9 illustrates one configuration of the power transmitting unit.

As shown, the power transmitting unit 950 may include four sourceresonating units 910, 920, 930, and 940. The four source resonatingunits 910, 920, 930, and 940 may be formed as a single resonator, or maybe formed as an array as illustrated in FIG. 10. Other configurationsand arrangements of source resonators are also possible.

In FIG. 9, when a wake-up request signal is transmitted from the sourceresonating unit 910 to a target device 960, the target device 960 may bedetected through a response signal in response to the wake-up requestsignal. The wake-up request signal may include information on an ID ofthe source resonating unit 910. The communication unit of FIG. 8 mayperform out-band communication using a frequency assigned for datacommunication, and the power transmitting unit 830 of FIG. 8 may performin-band communication for transmitting or receiving data to or from atarget device using a resonance frequency. Accordingly, the responsesignal in response to the wake-up request signal may be received to thewireless power transmitter 800 through the in-band communication or theout-band communication.

When no response signal in response to the wake-up request signal isreceived for a predetermined period of time, switching to the nextsource resonating unit 920 may be performed. If no response signal isreceived for a predetermined period of time after a wake-up requestsignal is transmitted, the source resonating unit 920 may be maintainedto be OFF. In the same or a similar manner, a target device 970 may bedetected in the source resonating units 930 and 940.

As described above, the source resonating units 910, 920, 930, and 940may be sequentially turned ON or OFF, and may broadcast a wake-uprequest signal, thereby detecting which source resonating unit locatedadjacent to a target device.

The source resonating units 910, 920, 930, and 940 may be respectivelyidentified by IDs of the source resonating units 910, 920, 930, and 940.The controller 820 of FIG. 8 may also recognize locations of the one ormore of plurality of target devices using the IDs of the sourceresonating units 910, 920, 930, and 940, respectively.

FIG. 10 illustrates one configuration of the source resonating unit 910of FIG. 9. As illustrated in FIG. 10, the source resonating unit 910 mayinclude at least four source resonators, for example source resonators911, 913, 915, and 917 that form an array. The source resonating unit831 of FIG. 8 may also be configured as illustrated in FIG. 10.

Additionally, the source resonating unit 910 or the source resonatorunit 831 may include a single source resonator, differently from FIG.10.

FIG. 11 illustrates one configuration of a wireless power receiver.

As shown, a wireless power receiver 1100 may include a communicationunit 1110, a power receiving unit 1120, and a controller 1130.Additionally, the wireless power receiver 1100 may further include apower supply unit 1150, and a load path switch 1140.

The communication unit 1110 may receive a wake-up request signal fromthe wireless power transmitter 800 of FIG. 8, and may transmit aresponse signal in response to the wake-up request signal to thewireless power transmitter 800. The response signal may includeinformation on an ID of the wireless power receiver 1100, information onan ID of a neighboring source resonating unit received from theneighboring source resonating unit, and/or information on the amount ofpower to be used in the wireless power receiver 1100.

Additionally, the communication unit 1110 may receive the information onthe ID of the neighboring source resonating unit through in-bandcommunication from the neighboring source resonating unit, and maytransmit the received information to the wireless power transmitter 800via out-band communication.

The term “in-band” communication(s), as used herein, meanscommunication(s) in which information (such as, for example, controlinformation, data and/or metadata) is transmitted in the same frequencyband, and/or on the same channel, as used for power transmission.According to one or more embodiments, the frequency may be a resonancefrequency. And, the term “out-band” communication(s), as used herein,means communication(s) in which information (such as, for example,control information, data and/or metadata) is transmitted in a separatefrequency band and/or using a separate or dedicated channel, than usedfor power transmission.

The power receiving unit 1120 may wirelessly receive power from a sourceresonating unit, or may form magnetic coupling with a target resonatorT_other of another wireless power receiver to wirelessly receive powerfrom the target resonator T_other. When an amount of power to be used inthe wireless power receiver 1100 is greater than an amount of power tobe used in the other wireless power receiver, the power receiving unit1120 may wirelessly receive power from the source resonating unit.Additionally, when the amount of the power to be used in the wirelesspower receiver 1100 is less than the amount of the power to be used inthe other wireless power receiver, the power receiving unit 1120 maywirelessly receive power from the target resonator T_other.

The power receiving unit 1120 may include a resonator 1121, a resonanceswitch 1123, and a matching controller 1125. The resonator 1121 mayperform the same function as the target resonator 121 of FIG. 1. Theresonance switch 1123 may be turned ON or OFF depending on a control ofthe controller 1130. The matching controller 1125 may perform impedancematching between the resonator 1121 and a load 1160, or impedancematching between the wireless power transmitter 800 and the resonator1121. The matching controller 1125 may detect a reflected wave, ordetect a change in impedance of the load 1160, to determine whether toperform the impedance matching. The resonator 1121 may be different insize or in the number of turns of a coil from the target resonatorT_other. The number of turns of the coil may be the number of times acoil-shaped resonator is wound, for instance.

When power reception is terminated, the controller 1130 may disconnectthe load 1160 by turning OFF the load path switch 1140. When the loadpath switch 1140 is turned OFF, the resonator 1121 cannot form magneticcoupling with any source resonator. The load 1160 may include, forexample, one or more of: a battery, a circuit for consuming power, or anexternal device detachably attached to the wireless power receiver 1100.

The controller 1130 may be configured to compute the power transmissionefficiency for power received wirelessly from the wireless powertransmitter 800. When the wireless power transmitter 800 broadcasts anamount Pt of power transmitted, the controller 1130 may compute a ratioof the amount Pt and an amount Pr of power received, to obtain the powertransmission efficiency. The controller 1130 may be configured toperiodically compute the power transmission efficiency, and may transmitinformation on the power transmission efficiency to the wireless powertransmitter 800 via the communication unit 1110.

Additionally, the controller 1130 may be configured to monitor a stateof the load 1160. When charging of the load 1160 is completed, thecontroller 1130 may notify the wireless power transmitter 800 ofcompletion of the charging of the load 1160.

The power supply unit 1150 may provide the load 1160 with power receivedwirelessly from the wireless power transmitter 800. The power supplyunit 1150 may include a rectification unit 1151, and a DC/DC converter1153. The rectification unit 1151 may generate a DC voltage byrectifying an AC voltage. The DC/DC converter 1153 may generate a DCvoltage required by the load 1160 by adjusting the level of the DCvoltage output from the rectification unit 1151.

FIG. 12 illustrates a method for controlling a wireless powertransmission.

In FIG. 12, a first wireless power receiver 1210 may be a high powerload, and a second wireless power receiver 1220 may be a low power load.

In operation 1201, the source resonating unit 831 may broadcast awake-up request signal. The wake-up request signal broadcasted by thesource resonating unit 831 may be received to the first wireless powerreceiver 1210. When a response signal is received from the firstwireless power receiver 1210 within a predetermined time interval T1,the wireless power transmitter 800 may detect the first wireless powerreceiver 1210. Additionally, the wireless power transmitter 800 maydetermine that the first wireless power receiver 1210 is located withina coverage of the source resonating unit 831. The response signal mayinclude information on the amount of power to be used in the firstwireless power receiver 1210, and information on an ID of the firstwireless power receiver 1210.

In operation 1203, the source resonating unit 835 may broadcast awake-up request signal. The wake-up request signal broadcasted by thesource resonating unit 835 may be received to the second wireless powerreceiver 1220. When a response signal is received from the secondwireless power receiver 1220 within a predetermined time interval T2,the wireless power transmitter 800 may detect the second wireless powerreceiver 1220. Additionally, the wireless power transmitter 800 maydetermine that the second wireless power receiver 1220 is located withina coverage area of the source resonating unit 835. The response signalmay include information on the amount of power to be used in the secondwireless power receiver 1220, and information on an ID of the secondwireless power receiver 1220.

Through operations 1201 and 1203, the wireless power transmitter 800 maydetect a plurality of target devices that wirelessly receive power.Operations 1201 and 1203 may be performed to detect the plurality oftarget devices. Accordingly, in operations 1201 and 1203, the wirelesspower transmitter 800 may sequentially broadcast wake-up request signalsusing a plurality of source resonating units, and may sequentiallyreceive response signals in response to the wake-up request signals fromthe plurality of target devices.

When target devices are detected via out-band communication, thedetector 810 of the wireless power transmitter 800 may broadcast wake-uprequest signals in operations 1205 and 1207. In response to the wake-uprequest signals, the first wireless power receiver 1210 and the secondwireless power receiver 1220 may transmit response signals to thewireless power transmitter 800 in operations 1209 and 1211.

The wireless power transmitter 800 may select the source resonating unit831 adjacent to the high power load, and may transmit power to the firstwireless power receiver 1210 through the source resonating unit 831 inoperation 1213. In operation 1215, the second wireless power receiver1220 may form a magnetic coupling with the first wireless power receiver1210, and may receive power from the first wireless power receiver 1210.

According to embodiments, it may be possible to efficiently performwireless power transmission to a plurality of wireless power receivers,thereby increasing an efficiency of a wireless power transmissionsystem. Additionally, it may be possible to efficiently transmit awireless power to different kinds of wireless power receivers.Furthermore, it may be possible to simultaneously transmit power todifferent kinds of wireless power receivers and the same kind ofwireless power receivers.

In one or more embodiments, a source resonator and/or a target resonatormay be configured as, for example, a helix coil structured resonator, aspiral coil structured resonator, a meta-structured resonator, and thelike.

An electromagnetic characteristic of many materials found in nature isthat they have a unique magnetic permeability or a unique permittivity.Most materials typically have a positive magnetic permeability or apositive permittivity. Thus, for these materials, a right hand rule maybe applied to an electric field, a magnetic field, and a pointing vectorand thus, the corresponding materials may be referred to as right handedmaterials (RHMs).

On the other hand, a material having a magnetic permeability or apermittivity which is not ordinarily found in nature or isartificially-designed (or man-made) may be referred to herein as a“metamaterial.” Metamaterials may be classified into an epsilon negative(ENG) material, a mu negative (MNG) material, a double negative (DNG)material, a negative refractive index (NRI) material, a left-handed (LH)material, and the like, based on a sign of the correspondingpermittivity or magnetic permeability.

The magnetic permeability may indicate a ratio between a magnetic fluxdensity occurring with respect to a predetermined magnetic field in acorresponding material and a magnetic flux density occurring withrespect to the predetermined magnetic field in a vacuum state. Themagnetic permeability and the permittivity, in some embodiments, may beused to determine a propagation constant of a corresponding material ina predetermined frequency or a predetermined wavelength. Anelectromagnetic characteristic of the corresponding material may bedetermined based on the magnetic permeability and the permittivity.According to an aspect, the metamaterial may be easily disposed in aresonance state without significant material size changes. This may bepractical for a relatively large wavelength area or a relatively lowfrequency area.

FIGS. 13 through 19B are diagrams illustrating various resonatorstructures.

FIG. 13 is a illustration of a two-dimensional (2D) resonator 1300.

As shown, the resonator 1300 having the 2D structure may include atransmission line, a capacitor 1320, a matcher 1330, and conductors 1341and 1342. The transmission line may include, for instance, a firstsignal conducting portion 1311, a second signal conducting portion 1312,and a ground conducting portion 1313.

The capacitor 1320 may be inserted or otherwise positioned in seriesbetween the first signal conducting portion 1311 and the second signalconducting portion 1312 such that an electric field may be confinedwithin the capacitor 1320, as illustrated in FIG. 13. In variousimplementations, the transmission line may include at least oneconductor in an upper portion of the transmission line, and may alsoinclude at least one conductor in a lower portion of the transmissionline. Current may flow through the at least one conductor disposed inthe upper portion of the transmission line and the at least oneconductor disposed in the lower portion of the transmission may beelectrically grounded.

As illustrated in FIG. 13, the resonator 1300 may be configured to havea generally 2D structure. The transmission line may include the firstsignal conducting portion 1311 and the second signal conducting portion1312 in the upper portion of the transmission line, and may include theground conducting portion 1313 in the lower portion of the transmissionline. As shown, the first signal conducting portion 1311 and the secondsignal conducting portion 1312 may be disposed to face the groundconducting portion 1313 with current flowing through the first signalconducting portion 1311 and the second signal conducting portion 1312.

In some implementations, one end of the first signal conducting portion1311 may be electrically connected (i.e., shorted) to the conductor1342, and another end of the first signal conducting portion 1311 may beconnected to the capacitor 1320. And one end of the second signalconducting portion 1312 may be grounded to the conductor 1341, andanother end of the second signal conducting portion 1312 may beconnected to the capacitor 1320. Accordingly, the first signalconducting portion 1311, the second signal conducting portion 1312, theground conducting portion 1313, and the conductors 1341 and 1342 may beconnected to each other such that the resonator 1300 may have anelectrically closed-loop structure. The term “closed-loop structure” asused herein, may include a polygonal structure, for example, a circularstructure, a rectangular structure, or the like that is a circuit thatis electrically closed. The capacitor 1320 may be inserted into anintermediate portion of the transmission line. For example, thecapacitor 1320 may be inserted into a space between the first signalconducting portion 1311 and the second signal conducting portion 1312.The capacitor 1320 may be configured, in some instances, as a lumpedelement, a distributed element, or the like. In one implementation, adistributed capacitor may be configured as a distributed element and mayinclude zigzagged conductor lines and a dielectric material having arelatively high permittivity between the zigzagged conductor lines.

When the capacitor 1320 is inserted into the transmission line, theresonator 1300 may have a property of a metamaterial, as discussedabove. For example, the resonator 1300 may have a negative magneticpermeability due to the capacitance of the capacitor 1320. If so, theresonator 1300 may also be referred to as a mu negative (MNG) resonator.Various criteria may be applied to determine the capacitance of thecapacitor 1320. For example, the various criteria may include forenabling the resonator 1300 to have the characteristic of themetamaterial may include one or more of the following: a criterion toenable the resonator 1300 to have a negative magnetic permeability in atarget frequency, a criterion to enable the resonator 1300 to have azeroth order resonance characteristic in the target frequency, or thelike. The resonator 1300, also referred to as the MNG resonator 1300,may also have a zeroth order resonance characteristic (i.e., having, asa resonance frequency, a frequency when a propagation constant is “0”).If the resonator 1300 has the zeroth order resonance characteristic, theresonance frequency may be independent with respect to a physical sizeof the MNG resonator 1300. Moreover, by appropriately designing thecapacitor 1320, the MNG resonator 1300 may sufficiently change theresonance frequency without significantly changing the physical size ofthe MNG resonator 1300.

In a near field, for instance, the electric field may be concentrated onthe capacitor 1320 inserted into the transmission line. Accordingly, dueto the capacitor 1320, the magnetic field may become dominant in thenear field. In one or more embodiments, the MNG resonator 1300 may havea relatively high Q-factor using the capacitor 1320 of the lumpedelement. Thus, it may be possible to enhance power transmissionefficiency. For example, the Q-factor indicates a level of an ohmic lossor a ratio of a reactance with respect to a resistance in the wirelesspower transmission. The efficiency of the wireless power transmissionmay increase according to an increase in the Q-factor.

The MNG resonator 1300 may include a matcher 1330 to be used inimpedance matching. For example, the matcher 1330 may be configured toappropriately determine and adjust the strength of a magnetic field ofthe MNG resonator 1300. Depending on the configuration, current may flowin the MNG resonator 1300 via a connector, or may flow out from the MNGresonator 1300 via the connector. The connector may be connected to theground conducting portion 1313 or the matcher 1330. In some instances,the power may be transferred through coupling without using a physicalconnection between the connector and the ground conducting portion 1313or the matcher 1330.

As illustrated in FIG. 13, the matcher 1330 may be positioned within theloop formed by the loop structure of the resonator 1300. The matcher1330 may adjust the impedance of the resonator 1300 by changing thephysical shape of the matcher 1330. For example, the matcher 1330 mayinclude the conductor 1331 to be used in the impedance matchingpositioned in a location that is separate from the ground conductingportion 1313 by a distance h. The impedance of the resonator 1300 may bechanged by adjusting the distance h.

Although not illustrated in FIG. 13, a controller may be provided tocontrol the matcher 1330. In this example, the matcher 1330 may changethe physical shape of the matcher 1330 based on a control signalgenerated by the controller. For example, the distance h between theconductor 1331 of the matcher 1330 and the ground conducting portion1313 may be increased or decreased based on the control signal.Accordingly, the physical shape of the matcher 1330 may be changedwhereby the impedance of the resonator 1300 may be adjusted.

In some instances, the matcher 1330 may be provided that is configuredas a passive element such as the conductor 1331, for example. Of course,if other embodiments, the matcher 1330 may be configured as an activeelement such as a diode, a transistor, or the like. If the activeelement is included in the matcher 1330, the active element may bedriven based on the control signal generated by the controller, and theimpedance of the resonator 1300 may be adjusted based on the controlsignal. For example, when the active element is a diode included in thematcher 1330, the impedance of the resonator 1300 may be adjusteddepending on whether the diode is in an ON state or in an OFF state.

In some instances, a magnetic core may be further provided to passthrough the MNG resonator 1300. The magnetic core may perform a functionof increasing the power transmission distance.

FIG. 14 is an illustration of a three-dimensional (3D) resonator 1400.

Referring to FIG. 14, the resonator 1400 having the 3D structure mayinclude a transmission line and a capacitor 1420. The transmission linemay include a first signal conducting portion 1411, a second signalconducting portion 1412, and a ground conducting portion 1413. Thecapacitor 1420 may be inserted, for instance, in series between thefirst signal conducting portion 1411 and the second signal conductingportion 1412 of the transmission link such that an electric field may beconfined within the capacitor 1420.

As illustrated in FIG. 14, the resonator 1400 may have a generally 3Dstructure. The transmission line may include the first signal conductingportion 1411 and the second signal conducting portion 1412 in an upperportion of the resonator 1400, and may include the ground conductingportion 1413 in a lower portion of the resonator 1400. The first signalconducting portion 1411 and the second signal conducting portion 1412may be disposed to face the ground conducting portion 1413. In thisarrangement, current may flow in an x direction through the first signalconducting portion 1411 and the second signal conducting portion 1412.Due to the current, a magnetic field H(W) may be formed in a −ydirection. However, it will be appreciated that the magnetic field H(W)might also be formed in the opposite direction (e.g., a +y direction) inother implementations.

In one or more embodiments, one end of the first signal conductingportion 1411 may be electrically connected (i.e., shorted) to theconductor 1442, and another end of the first signal conducting portion1411 may be connected to the capacitor 1420. One end of the secondsignal conducting portion 1412 may be grounded to the conductor 1441,and another end of the second signal conducting portion 1412 may beconnected to the capacitor 1420. Accordingly, the first signalconducting portion 1411, the second signal conducting portion 1412, theground conducting portion 1413, and the conductors 1441 and 1442 may beconnected to each other, whereby the resonator 1400 may have anelectrically closed-loop structure. As illustrated in FIG. 14, thecapacitor 1420 may be inserted or otherwise positioned between the firstsignal conducting portion 1411 and the second signal conducting portion1412. For example, the capacitor 1420 may be inserted into a spacebetween the first signal conducting portion 1411 and the second signalconducting portion 1412. The capacitor 1420 may include, for example, alumped element, a distributed element, and the like. In oneimplementation, a distributed capacitor having the shape of thedistributed element may include zigzagged conductor lines and adielectric material having a relatively high permittivity positionedbetween the zigzagged conductor lines.

When the capacitor 1420 is inserted into the transmission line, theresonator 1400 may have a property of a metamaterial, in some instances,as discussed above. For example, when the capacitor is configured as alumped element, the resonator 1400 may have the characteristic of themetamaterial. When the resonator 1400 has a negative magneticpermeability by appropriately adjusting the capacitance of the capacitor1420, the resonator 1400 may also be referred to as an MNG resonator.Various criteria may be applied to determine the capacitance of thecapacitor 1420. For example, the various criteria may include one ormore of the following: a criterion to enable the resonator 1400 to havethe characteristic of the metamaterial, a criterion to enable theresonator 1400 to have a negative magnetic permeability in a targetfrequency, a criterion to enable the resonator 1400 to have a zerothorder resonance characteristic in the target frequency, or the like.Based on at least one criterion among the aforementioned criteria, thecapacitance of the capacitor 1420 may be determined.

The resonator 1400, also referred to as the MNG resonator 1400, may havea zeroth order resonance characteristic (i.e., having, as a resonancefrequency, a frequency when a propagation constant is “0”). If theresonator 1400 has a zeroth order resonance characteristic, theresonance frequency may be independent with respect to a physical sizeof the MNG resonator 1400. Thus, by appropriately designing thecapacitor 1420, the MNG resonator 1400 may sufficiently change theresonance frequency without significantly changing the physical size ofthe MNG resonator 1400.

Referring to the MNG resonator 1400 of FIG. 14, in a near field, theelectric field may be concentrated on the capacitor 1420 inserted intothe transmission line. Accordingly, due to the capacitor 1420, themagnetic field may become dominant in the near field. Since the MNGresonator 1400 having the zeroth-order resonance characteristic may havecharacteristics similar to a magnetic dipole, the magnetic field maybecome dominant in the near field. A relatively small amount of theelectric field formed due to the insertion of the capacitor 1420 may beconcentrated on the capacitor 1420 and thus, the magnetic field maybecome further dominant. The MNG resonator 1400 may have a relativelyhigh Q-factor using the capacitor 1420 of the lumped element and thus,it may be possible to enhance an efficiency of power transmission. Also,the MNG resonator 1400 may include the matcher 1430 to be used inimpedance matching. The matcher 1430 may be configured to appropriatelyadjust the strength of magnetic field of the MNG resonator 1400. Theimpedance of the MNG resonator 1400 may be determined by the matcher1430. In one or more embodiments, current may flow in the MNG resonator1400 via a connector 1440, or may flow out from the MNG resonator 1400via the connector 1440. And the connector 1440 may be connected to theground conducting portion 1413 or the matcher 1430.

As illustrated in FIG. 14, the matcher 1430 may be positioned within theloop formed by the loop structure of the resonator 1400. The matcher1430 may be configured to adjust the impedance of the resonator 1400 bychanging the physical shape of the matcher 1430. For example, thematcher 1430 may include the conductor 1431 to be used in the impedancematching in a location separate from the ground conducting portion 1413by a distance h.

The impedance of the resonator 1400 may be changed by adjusting thedistance h. In some implementations, a controller may be provided tocontrol the matcher 1430. In this case, the matcher 1430 may change thephysical shape of the matcher 1430 based on a control signal generatedby the controller. For example, the distance h between the conductor1431 of the matcher 1430 and the ground conducting portion 1413 may beincreased or decreased based on the control signal. Accordingly, thephysical shape of the matcher 1430 may be changed such that theimpedance of the resonator 1400 may be adjusted. The distance h betweenthe conductor 1431 of the matcher 1430 and the ground conducting portion1413 may be adjusted using a variety of schemes. For example, one ormore conductors may be included in the matcher 1430 and the distance hmay be adjusted by adaptively activating one of the conductors.Alternatively or additionally, the distance h may be adjusted byadjusting the physical location of the conductor 1431 up and down. Forinstance, the distance h may be controlled based on the control signalof the controller. The controller may generate the control signal usingvarious factors. As illustrated in FIG. 14, the matcher 1430 may beconfigured as a passive element such as the conductor 1431, forinstance. Of course, in other embodiments, the matcher 1430 may beconfigured as an active element such as a diode, a transistor, or thelike. If the active element is included in the matcher 1430, the activeelement may be driven based on the control signal generated by thecontroller, and the impedance of the resonator 1400 may be adjustedbased on the control signal. For example, if the active element is adiode included in the matcher 1430, the impedance of the resonator 1400may be adjusted depending on whether the diode is in an ON state or inan OFF state.

In some implementations, a magnetic core may be further provided to passthrough the resonator 1400 configured as the MNG resonator. The magneticcore may increase the power transmission distance.

FIG. 15 illustrates a resonator 1500 for a wireless power transmissionconfigured as a bulky type.

As used herein, the term “bulky type” may refer to a seamless connectionconnecting at least two parts in an integrated form.

Referring to FIG. 15, a first signal conducting portion 1511 and aconductor 1542 may be integrally formed, rather than being separatelymanufactured and being connected to each other. Similarly, a secondsignal conducting portion 1512 and a conductor 1541 may also beintegrally manufactured.

When the second signal conducting portion 1512 and the conductor 1541are separately manufactured and then are connected to each other, a lossof conduction may occur due to a seam 1550. The second signal conductingportion 1512 and the conductor 1541 may be connected to each otherwithout using a separate seam (i.e., seamlessly connected to eachother). Accordingly, it may be possible to decrease a conductor losscaused by the seam 1550. Similarly, the second signal conducting portion1512 and a ground conducting portion 1513 may be seamlessly andintegrally manufactured. In addition, the first signal conductingportion 1511 and the ground conducting portion 1513 may be seamlesslyand/or integrally manufactured.

A matcher 1530 may be provided that is similarly constructed asdescribed herein in one or more embodiments.

FIG. 16 illustrates a resonator 1600 for a wireless power transmission,configured as a hollow type.

Referring to FIG. 16, each of a first signal conducting portion 1611, asecond signal conducting portion 1612, a ground conducting portion 1613,and conductors 1641 and 1642 of the resonator 1600 configured as thehollow type structure. As used herein the term “hollow type” refers to aconfiguration that may include an empty space inside.

For a given resonance frequency, an active current may be modeled toflow in only a portion of the first signal conducting portion 1611instead of all of the first signal conducting portion 1611, a portion ofthe second signal conducting portion 1612 instead of all of the secondsignal conducting portion 1612, a portion of the ground conductingportion 1613 instead of all of the ground conducting portion 1613, andportions of the conductors 1641 and 1642 instead of all of theconductors 1641 and 1642. When a depth of each of the first signalconducting portion 1611, the second signal conducting portion 1612, theground conducting portion 1613, and the conductors 1641 and 1642 issignificantly deeper than a corresponding skin depth in thepredetermined resonance frequency, such a structure may be ineffective.The significantly deeper depth may, however, increase the weight ormanufacturing costs of the resonator 1600, in some instances.

Accordingly, for the given resonance frequency, the depth of each of thefirst signal conducting portion 1611, the second signal conductingportion 1612, the ground conducting portion 1613, and the conductors1641 and 1642 may be appropriately determined based on the correspondingskin depth of each of the first signal conducting portion 1611, thesecond signal conducting portion 1612, the ground conducting portion1613, and the conductors 1641 and 1642. When one or more of the firstsignal conducting portion 1611, the second signal conducting portion1612, the ground conducting portion 1613, and the conductors 1641 and1642 have an appropriate depth deeper than a corresponding skin depth,the resonator 1600 may be manufactured to be lighter, and themanufacturing costs of the resonator 1600 may also decrease.

For example, as illustrated in FIG. 16, the depth of the second signalconducting portion 1612 (as further illustrated in the enlarged viewregion 1660 indicated by a circle) may be determined as “d” mm, and dmay be determined according to

$d = {\frac{1}{\sqrt{\pi\; f\;\mu\;\sigma}}.}$Here, f denotes a frequency, μ denotes a magnetic permeability, and σdenotes a conductor constant. In one implementation, when the firstsignal conducting portion 1611, the second signal conducting portion1612, the ground conducting portion 1613, and the conductors 1641 and1642 are made of copper and they have a conductivity of 5.8×10⁷ siemensper meter (S·m⁻¹), the skin depth may be about 0.6 mm with respect to 10kHz of the resonance frequency, and the skin depth may be about 0.006 mmwith respect to 100 MHz of the resonance frequency.

A capacitor 1620 and a matcher 1630 may be provided that are similarlyconstructed as described herein in one or more embodiments.

FIG. 17 illustrates a resonator 1700 for a wireless power transmissionusing a parallel-sheet configuration.

Referring to FIG. 17, the parallel-sheet configuration may be applicableto a first signal conducting portion 1711 and a second signal conductingportion 1712 included in the resonator 1700.

The first signal conducting portion 1711 and/or the second signalconducting portion 1712 may not be perfect conductors, and thus may havean inherent resistance. Due to this resistance, an ohmic loss may occur.The ohmic loss may decrease a Q-factor and may also decrease a couplingeffect.

By applying the parallel-sheet configuration to each of the first signalconducting portion 1711 and the second signal conducting portion 1712,it may be possible to decrease the ohmic loss, and to increase theQ-factor and the coupling effect. Referring to the enlarged view portion1770 (indicated by a circle in FIG. 17), when the parallel-sheetconfiguration is applied, each of the first signal conducting portion1711 and the second signal conducting portion 1712 may include aplurality of conductor lines. The plurality of conductor lines may bedisposed in parallel, and may be electrically connected (i.e., shorted)at an end portion of each of the first signal conducting portion 1711and the second signal conducting portion 1712.

As described above, when the parallel-sheet configuration is applied toone or both of the first signal conducting portion 1711 and the secondsignal conducting portion 1712, the plurality of conductor lines may bedisposed in parallel. Accordingly, the sum of resistances having theconductor lines may decrease. Consequently, the resistance loss maydecrease, and the Q-factor and the coupling effect may increase.

A capacitor 1720 and a matcher 1730 positioned on the ground conductingportion 1713 may be provided that are similarly constructed as describedherein in one or more embodiments.

FIG. 18 illustrates a resonator 1800 for a wireless power transmissionincluding a distributed capacitor.

Referring to FIG. 18, a capacitor 1820 included in the resonator 1800 isconfigured for the wireless power transmission. A capacitor used as alumped element may have a relatively high equivalent series resistance(ESR). A variety of schemes have been proposed to decrease the ESRcontained in the capacitor of the lumped element. According to anexample embodiment, by using the capacitor 1820 as a distributedelement, it may be possible to decrease the ESR. As will be appreciated,a loss caused by the ESR may decrease a Q-factor and a coupling effect.

As illustrated in FIG. 18, the capacitor 1820 may be configured as aconductive line having the zigzagged structure.

By employing the capacitor 1820 as the distributed element, it may bepossible to decrease the loss occurring due to the ESR in someinstances. In addition, by disposing a plurality of capacitors as lumpedelements, it may be possible to decrease the loss occurring due to theESR. Since a resistance of the capacitors as the lumped elementsdecreases through a parallel connection, active resistances ofparallel-connected capacitors as the lumped elements may also decreasesuch that the loss occurring due to the ESR may decrease. For example,by employing ten capacitors of 1 pF each instead of using a singlecapacitor of 10 pF, it may be possible to decrease the loss occurringdue to the ESR.

FIG. 19A illustrates one embodiment of the matcher 1330 used in theresonator 1300 illustrated in FIG. 13, and FIG. 19B illustrates anexample of the matcher 1430 used in the resonator 1400 illustrated inFIG. 14.

FIG. 19A illustrates a portion of the resonator 1300 of FIG. 13including the matcher 1330, and FIG. 19B illustrates a portion of theresonator 1400 of FIG. 14 including the matcher 1430.

Referring to FIG. 19A, the matcher 1330 may include the conductor 1331,a conductor 1332, and a conductor 1333. The conductors 1332 and 1333 maybe connected to the ground conducting portion 1313 and the conductor1331. The impedance of the 2D resonator may be determined based on adistance h between the conductor 1331 and the ground conducting portion1313. The distance h between the conductor 1331 and the groundconducting portion 1313 may be controlled by the controller. Thedistance h between the conductor 1331 and the ground conducting portion1313 may be adjusted using a variety of schemes. For example, thevariety of schemes may include one or more of the following: a scheme ofadjusting the distance h by adaptively activating one of the conductors1331, 1332, and 1333, a scheme of adjusting the physical location of theconductor 1331 up and down, and/or the like.

Referring to FIG. 19B, the matcher 1430 may include the conductor 1431,a conductor 1432, a conductor 1433 and conductors 941 and 942. Theconductors 1432 and 1433 may be connected to the ground conductingportion 1413 and the conductor 1431. The impedance of the 3D resonatormay be determined based on a distance h between the conductor 1431 andthe ground conducting portion 1413. The distance h between the conductor1431 and the ground conducting portion 1413 may be controlled by thecontroller, for example. Similar to the matcher 1330 illustrated in FIG.19A, in the matcher 1430, the distance h between the conductor 1431 andthe ground conducting portion 1413 may be adjusted using a variety ofschemes. For example, the variety of schemes may include one or more ofthe following: a scheme of adjusting the distance h by adaptivelyactivating one of the conductors 1431, 1432, and 1433, a scheme ofadjusting the physical location of the conductor 1431 up and down, andthe like.

In some implementations, the matcher may include an active element.Thus, a scheme of adjusting an impedance of a resonator using the activeelement may be similar to the examples described above. For example, theimpedance of the resonator may be adjusted by changing a path of currentflowing through the matcher using the active element.

FIG. 20 illustrates one equivalent circuit of the resonator 1300 of FIG.13.

The resonator 1300 of FIG. 13 used in a wireless power transmission maybe modeled to the equivalent circuit of FIG. 20. In the equivalentcircuit depicted in FIG. 20, L_(R) denotes an inductance of the powertransmission line, C_(L) denotes the capacitor 1320 that is inserted ina form of a lumped element in the middle of the power transmission line,and C_(R) denotes a capacitance between the power transmissions and/orground of FIG. 13.

In some instances, the resonator 1300 may have a zeroth resonancecharacteristic. For example, when a propagation constant is “0”, theresonator 1300 may be assumed to have ω_(MZR) as a resonance frequency.The resonance frequency ω_(MZR) may be expressed by Equation 2.

$\begin{matrix}{\omega_{MZR} = \frac{1}{\sqrt{L_{R}C_{L}}}} & \left\lbrack {{Equation}\mspace{14mu} 2} \right\rbrack\end{matrix}$

In Equation 2, MZR denotes a Mu zero resonator.

Referring to Equation 2, the resonance frequency ω_(MZR) of theresonator 1300 may be determined by

L_(R)/C_(L).A physical size of the resonator 1300 and the resonance frequencyω_(MZR) may be independent with respect to each other. Since thephysical sizes are independent with respect to each other, the physicalsize of the resonator 1300 may be sufficiently reduced.

The units described herein may be implemented using hardware components,software components, or a combination thereof. For example, a processingdevice may be implemented using one or more general-purpose or specialpurpose computers, such as, for example, a processor, a controller andan arithmetic logic unit, a digital signal processor, a microcomputer, afield programmable array, a programmable logic unit, a microprocessor orany other device capable of responding to and executing instructions ina defined manner. The processing device may run an operating system (OS)and one or more software applications that run on the OS. The processingdevice also may access, store, manipulate, process, and create data inresponse to execution of the software. For purpose of simplicity, thedescription of a processing device is used as singular; however, oneskilled in the art will appreciated that a processing device may includemultiple processing elements and multiple types of processing elements.For example, a processing device may include multiple processors or aprocessor and a controller. In addition, different processingconfigurations are possible, such a parallel processors.

The software may include a computer program, a piece of code, aninstruction, or some combination thereof, for independently orcollectively instructing or configuring the processing device to operateas desired. Software and data may be embodied permanently or temporarilyin any type of machine, component, physical or virtual equipment,computer storage medium or device, or in a propagated signal wavecapable of providing instructions or data to or being interpreted by theprocessing device. The software also may be distributed over networkcoupled computer systems so that the software is stored and executed ina distributed fashion. In particular, the software and data may bestored by one or more computer readable recording mediums. The computerreadable recording medium may include any data storage device that canstore data which can be thereafter read by a computer system orprocessing device. Examples of the computer readable recording mediuminclude read-only memory (ROM), random-access memory (RAM), CD-ROMs,magnetic tapes, floppy disks, optical data storage devices. Also,functional programs, codes, and code segments for accomplishing theexample embodiments disclosed herein can be easily construed byprogrammers skilled in the art to which the embodiments pertain based onand using the flow diagrams and block diagrams of the figures and theircorresponding descriptions as provided herein.

A number of examples have been described above. Nevertheless, it shouldbe understood that various modifications may be made. For example,suitable results may be achieved if the described techniques areperformed in a different order and/or if components in a describedsystem, architecture, device, or circuit are combined in a differentmanner and/or replaced or supplemented by other components or theirequivalents. Accordingly, other implementations are within the scope ofthe following claims.

What is claimed is:
 1. A wireless power transmitting apparatus, theapparatus comprising: a power transmitter having a plurality of powertransmitting elements; and a controller configured to: detect a firsttarget device configured to receive wireless power, receive informationon an amount of power required by the first target device andidentification (ID) information of the first target device from thefirst target device, select at least one power transmitting element fromamong the plurality of power transmitting elements, based on the IDinformation of the first target device, and control the powertransmitter to transmit, to the first target device, wireless powercorresponding to the information on the amount of power required by thefirst target device via the selected at least one power transmittingelement.
 2. The wireless power transmitting apparatus of claim 1,wherein the controller further configured to control the powertransmitter to transmit, to a second target device, wireless power viaat least one power transmitting element selected from among theplurality of power transmitting elements based on ID information of thesecond target device.
 3. The wireless power transmitting apparatus ofclaim 2, wherein the at least one power transmitting element selectedbased on the ID information of the first target device and the at leastone power transmitting element selected based on the ID information ofthe second target device are arranged in an array.
 4. The wireless powertransmitting apparatus of claim 2, an amount of power transmitted by theat least one power transmitting element selected based on the IDinformation of the first target device is different from an amount ofpower transmitted by the at least one power transmitting elementselected based on the ID information of the second target device.
 5. Thewireless power transmitting apparatus of claim 2, wherein a frequency ofwireless power by the at least one power transmitting element selectedbased on the ID information of the first target device is different froma frequency of wireless power by the at least one power transmittingelement selected based on the ID information of the second targetdevice.
 6. The wireless power transmitting apparatus of claim 1, whereinthe controller further configure to: detect a second target deviceconfigured to receive wireless power, receive information on an amountof power required by the second target device and ID information of thesecond target device from the second target device, select at least onepower transmitting element from among the plurality of powertransmitting elements, based on the ID information of the second targetdevice, and control the power transmitter to transmit, to the secondtarget device, wireless power corresponding to the information on theamount of power required by the second target device via the at leastone power transmitting element selected based on the ID information ofthe second target device.
 7. The wireless power transmitting apparatusof claim 1, wherein the ID information corresponds to locationinformation of the plurality of power transmitting elements.
 8. Thewireless power transmitting apparatus of claim 7, wherein the locationinformation indicates a location corresponding to at least one of powertransmitting element among the plurality of power transmitting elements.9. The wireless power transmitting apparatus of claim 1, wherein thecontroller further configured to stop supplying power to the pluralityof power transmitting elements except to the selected at least onetransmitting element, in response to the at least one transmittingelement selected based on the ID information of the first target device.10. A wireless power transmitting method performed by an electronicdevice, the method comprising: detecting a first target deviceconfigured to receive wireless power; receiving information on an amountof power required by the first target device and identification (ID)information of the first target device from the first target device;selecting at least one power transmitting element from among a pluralityof power transmitting elements of the electronic device, based on the IDinformation of the first target device; and transmitting, to the firsttarget device, wireless power corresponding to the information on theamount of power required by the first target device via the selected atleast one power transmitting element.
 11. The wireless powertransmitting method of claim 10, further comprising transmitting, to asecond target device, wireless power via at least one power transmittingelement selected from among the plurality of power transmitting elementsbased on ID information of the second target device.
 12. The wirelesspower transmitting method of claim 11, wherein the at least one powertransmitting element selected based on the ID information of the firsttarget device and the at least one power transmitting element selectedbased on the ID information of the second target device are arranged inan array.
 13. The wireless power transmitting method of claim 11, anamount of power transmitted by the at least one power transmittingelement selected based on the ID information of the first target deviceis different from an amount of power transmitted by the at least onepower transmitting element selected based on the ID information of thesecond target device.
 14. The wireless power transmitting method ofclaim 11, wherein a frequency of wireless power by the at least onepower transmitting element selected based on the ID information of thefirst target device is different from a frequency of wireless power bythe at least one power transmitting element selected based on the IDinformation of the second target device.
 15. The wireless powertransmitting method of claim 10, further comprising: detecting a secondtarget device configured to receive wireless power, receivinginformation on an amount of power required by the second target deviceand ID information of the second target device from the second targetdevice, selecting at least one power transmitting element from among theplurality of power transmitting elements, based on the ID information ofthe second target device, and transmitting, to the second target device,wireless power corresponding to the information on the amount of powerrequired by the second target device via the at least one powertransmitting element selected based on the ID information of the secondtarget device.
 16. The wireless power transmitting method of claim 10,wherein the ID information corresponds to the location information ofthe plurality of power transmitting elements.
 17. The wireless powertransmitting method of claim 16, wherein the location informationindicates a location corresponding to at least one of power transmittingelement among the plurality of power transmitting elements.
 18. Thewireless power transmitting method of claim 10, further comprisingstopping supplying power to the plurality of power transmitting elementsexcept to the selected at least one power transmitting element, inresponse to the at least one power transmitting element selected basedon the ID information of the first target device.
 19. A non-transitorycomputer-readable storage medium storing instructions, which whenexecuted by a processor, cause the processor to implement the method ofclaim 10.